A slow downward trend with a slight rise which is being sold as catastrophic end of the world sort of event. Historically, the planet seems to have a maximum temp that it never exceeds:
Only about 1.5-2 degrees warmer than present. Also note the downward trend, crammed into the far right hand end of the graph.
What interests me is the cyclic pattern of about 110,000 years when the planet is plunged into a global ice age which seems to last a lot longer than those short warm periods. Someone better than me at math could apply a Fourier Transformation to this and show the various event cycles that result in this periodic function. Maybe there's a small black hole in a wildly elliptical orbit that does this by disrupting the asteroid belt and bringing on extinction level meteor impacts.
Whatever, this solution to the problem of global warming, involving spraying the upper atmosphere with Sulfur compounds to reduce the sunlight coming in leaves me unimpressed. The last time this was done, the dinosaurs went extinct.